Power operated case shift mechanism for typewriting machines



Patented Apr. 13, 1948 T OFFICE CASE SHIFT MECHA- NISM FOR TYPEWRITINGMACHINES POWER OPERATED Ronald D. Dodge,

to International tion, York Poughkeepsie, N.

Business Machines Corpora- New York, N. Y., a corporation of New Y.,`assignor Application November 10, 1944, Serial No. 562,'789

9 Claims. (o. 197- 74)` This invention relates to typewriting machines.

'I'he principal object of the present invention is to provide animproved power Operating mechanism for typewriting machines.

An object is to provide a power Operating mech anism which is smootherand more positive in its action upon the devices operated thereby.

An object is to provide a power Operating mechanism which actuatespositively in both directions instead of positively in one directionwith im- 1positive restorationby a spring in the other direcion.

An object is to provide a power Operating device for typewritingmachines which is especially suitable for Operating the shift mechanism.

An object is to provide a power operated shift mechanism which isSimpler, more positive, and quieter in its operation than power shiftmechanisms heretofore used.

Other objects of the invention will be pointed out in the followingdescription and claims and illustrated in the accompanying drawings,which disclose, by way of example, the principle of the invention andthe best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a vertical section through a power mechanism embodying thepresent invention showing the parts of the power mechanism in the normalposition.

Fig. 2 is a vertical section showing certain of the parts in partlyoperated position.

The invention is shown in the drawings as applied to the well-knownE1ectromatic" typewriter. It will be understood, however, that theinvention is not limited in its application to the specific form oftypewriter selected for purposes of illustration but may be applied toother typewriters equally as well.

In the well-known "Electromatic" typewriter the power mechanismcomprises a main power roller which is designated I in the drawings withwhich cooperates a series of cam units, each controlled by a key andconnected to operated devices such as type bars, the Shift mechanism,the carriage return mechanism, and so on. The present inventioncontemplates making use of this main power roller ID in conjunction witha second power roller and a modified form of cam unit to obtain asmoother and more positive operation of devices in such machines,particularly the Shift mechanism which ordinarily is fairly noisy on aocount of the mass of mechanism which must be moved by the shift cam unitto eiiect the shiiting of the type bars from one case position to theother.

i 2 In Fig. 1 the'numeral ll designates a portion of the type basketwhich is mounted on leaf springs` |2 in a well-known way and whichincludes an adjustable stop |3 comprisin g a headed screw threaded intoa lug Ha forming part of the type basket. The head of the screw I 3limits movement of the basket to its upper position, in which the lowercase characters will be printed, by tcooperation with a stop post orstrip 14 secured to the main frame work, the post being provided with ahole through which the shank of the screw !3 passes. There are four ofthe springs I2 arranged in two pairs at the sides of the machine to form"parallel motion links which cause the type basket to move insubstantially a straight line through the relatively short distancenecessary to aifect a changein case. The stop screw !3 carries athreaded collar |5 which limits the downward movement of the type basketto the upper case position by engaging the upper side of the -post 14.It will be understood that there are two of the stop screws |3 and twoof the posts i [4 located at the sides of the machines to hold` the typebasket level in either of its case shifted positions. i i i Adjustablymountedon the sides of the type basket I I are the arms Hi of whichthere is one on to a cross shaft !8 suitably journaled in the frame iwork. By rocking the shaft |8 counterclockwise, the type basket l iwillbe drawn downwardly to the upper case position. -For the purpose ofeffecting this movement of the type basket, there is provided a poweroperated mechanism which is controlledby a Shift key |9 pivoted on thefulcrum wire` 20 extending across the machine and acting as a pivot forall of the keys of the keyboard. i

This power Operating mechanism includes the main power roller o whichcooperates with the usual cam units Operating the type bars (not shown)in thevbasket I and a second power roller 2|` mounted on theishaft 22.This second power roller ZI 'is driven by the main power roller Ztthrough a 'belt 23 which passes around pulley groovesformed in the endsof the power rollers I!) and 2 l. i t

Pivoted on a cross rod 24 which pivot's the front cam units (not shown)which operate the type bars and other devices is a cam unit 25comprising an assembly including a frame having the general form ofaright angle lever, one of the arms of which is connected by a link 26 toa rock lever 21 pivotecl at 28 on the main frame work of 'the machine.An arm of lever 21 is connected by 'pivoted at 259 is a a pin and slotconnection 29 to one of the arms l'l whereby rocking of lever 21 in acounterclockwise direction will result in drawing down the type basketto the upper case position.

The cam unit 25 includes a frame 25a in which a substantially circularcam 256 is eccentrically pivotally mounted at 250 and the cam 25b isprovided with a circular cutaway portion 25d which normally confrontsthe power roller 2! to provide a clearance which normally prevents thecam 25b' from being rotated by the power roller 2 l When the type basketis in the lower case position the periphery of the cam 2517 is clearofthe main power roller n. r

The cam 25b is provided with two projections 256 which may take the formof bosses and are located equal distances on diametrically oppositesides of the 2517. In the normal position of the cam 251), as shown inFig. 1, a spring actuated arm 253* engages theside of the lower boss 256and tends to urge the cam 2517 in a clockwise direction. The arm 257' ispivoted at 25g to frame 25a 'of the cam unit and is urged .in a'clockwise direction by torsion spring 2517.. .The cam 251) is alsoprovided with two stop lugs 252', 257'. Also detent lever 2579 having abent over lug 251 normally engaging the lug 252' thus preventing the cam25b from rotating clockwise. The key!!! is provided with an extensionl9a having a-slot embracing a pin 25172 carried by the arm of the detentlever 257c opposite the one. carrying thelug engaging 251.

The operation of these parts will now be explained in detail.

It will be assumed that the operator desires to Shift type basket II toenable upper case type characters on the type ,bars to print on the worksheet. To effect this result the operator depresses the Shift 'key l9.This causes the detent lever Zk to rock in counterclockwise directionthereby releasing the lug 251 on the detent lever 2515 from the lug 251.This permits'the spring arm 25f to rotate the cam 25b a limited amountin a clockwise direction thereby causing the circular portion, of thecam 251 to engage the periphery ofpower roller zl. The cam 25b is nowdriven positively by the power roller 2| through half a revolution tothe position of Fig. 2. Thus the cam 2519 in effect rolls over theperiphery of the roller 21 and, on account of the eccentric mounting ofthe cam 25b on the cam unit frame; causes the frame of the cam unit 25to be rocked clockwise therebythrusting upwardly on the link 26 and,through the lever 21, arms ll, and the links lsa, drawing down the typebasket to the upper case position.

The case Shift key 19 will either be held down by the operator whileOperating the desired character key or may be locked down by means ofthe usual shiit lock key (not shown) i The lugs 25i, 257' are so locatedon the cam 25b on opposite sides of the pivot 251) that when the detentlever 2570 is operated by the key as aforesaid and held in operatedposition, it moves out of engagement with the lug 25` into the path ofthe lug 257'. In other words, the lug 250' is located at a slightlygreater distance from pivot 25c but almost'diametri'cally opposite thelug 25' Thus, When the cam 2519 is rotated a half revolution the lug257" engages the lug ormed in the detent lever '.257c, as in Fig. 2, and

prevents further rotation of the cam 25b as long as the Shift key l9 isheld depressed As a result of the depression of the key the type basketpivot 250 of the crcular cam V a toggle spring If now the operatorreleases the Shift key lt, i

the detent lever 257* will be rocked back to its originual position;shown in Fig. 1, and will therebyremovethe lug on the detent lever 2510from engagement with the lug 259". This permits the cam 2517 to engagepower roller lil and to make another half revolution, positivelyrestoring the parts'to the position oi Fig. 1. Thiis the type basket ismoved positively back to the position of Flg. 1 but the initial andterminal velocities of the type basket will below preventing the stopscrew &3 from slamrning against the post l 4.

In order to yieldingly hold the lever 27 in either of its shiftedpositions there is provided 331 which engages pins carried by the end oflever zl m'oving the bar and slot connection 29 and by the main iframe;respectively. The spring se also causes the leverzl to move a littlefurther irieach direction than the lever is actuated by the cam unit 25for the purpose of carrying the cam unit to the position of Fig. 1, inwhich the cam 251 is clear of the power roller lil, or to the positionof Fig. 2, in which the cam is clear of theipower roller ti. Withoutspring, the cam might drag on one or the other of the power rollers saand 2! resulting in wear of the power' rollexi This spring is helpfulin' preventing wear because the surface of the power roller is usuallyrubber which would have a groove worn in it if' the cam dragged One ofthe main advantages of the mechanism described above is that the typebasket Shift mechanism can be simplified. Heretofore it has beencustomary to use the Shift mechanism disclosed in Patent No. l,945,097in which the cam unit actuates a T-lever which is moved to alternateoperative positions by a connection to the shift key. This Constructionwas made necessary by the fact that' the Shift cam unit usually hasa idouble-lobed cam, and operates positively in only' one direction, beingrestored cycle of operation of the cam unit and then other direction byanthe necessity for using moved positively in the other half cyclewithout a T-lever which is shifted by the key between half cycles. Thus,relatively simple connections between the cam unit and the Shiftmechanism may be used in the present case witha more positive actionsince the action is more direct and much Simpler. e

Another advantage oi the mechanism disclosed herein is that the touchrequired to actuate the shift key is greatly light-.ened and is nogreater than the touch required for the character' keys because of theelimination of the T-lever which imposes a certain amount of additionalload on theshift key.

A further advantage is by a spring. Onthe that the 'mecham'sm of aneccentric from and its approach to the dead i center position iseffected with slow motion. It

follows that the type basket will be brought to a r stop smoothly beforethe power roller loses complete control of the cam 251).

A distinct advantage of the mechanism is that the operation of the typebasket is more closely synchronized with the operation of the. shiftkey. When the shift key is in the position of Fig. 1, the type basketmust necessarily be in lower case position since only in this positio isthe stop lug 252', which determines the position 'of the cam in Fig. 1,in engagement with the lug on lever 2576. In other words, if the shiftkey were merely ipped with the finger and not held down, the cam 251)will always make `a complete revolution thus drawing the type basketdown to its upper case position and then immediately thrusting it backto lower case position. In the shift mechanism disclosed in the abovepatent, if the key is flipped instead of being held down, the cam unitwill draw the type basket down to upper case position but the T-leverwill be restored immediately along with the key with the result that thesecond operation of the cam unit merely tends to repeat the efiect onthe type basket and leaves the type basket in the upper case position.

While there have been shown and described and pointed out thefundamental novel features of the invention, as applied to a singleembodiment, it will be understood that various omissions andsubstitutions and changes in the form and details of the deviceillustrated and in its operation may be made by those skilled in the artwithout departing from the spirit of the invention. It is the intentionthrefore to be limited only as indicated by the scope of the followingclaims.

What is claimed is:

1. In a power operated typewriter, a case Shiftablepart, a main powerroller, a second power roller; a cam unit connected to said caseShiftable part and including a cam alternately operatively engageablewith both said power rollers to effect both a positive shiit of saidcase shi'itable part and a positive restoring movement of said part, andincluding releasable means for causing the alternate engagement of saidcam with said power rollers; and a shift key for controlling thereleasable means.

2. A power Operating device for typewriters and the like comprising apair of power drivers, a member adapted for actuating a device of thetypewriter, cam means mounted on said member for engagement with one orthe other of said drivers; means to cause the cam means to engage and bepositively operated by first one and then by the other of said drivers,said cam means, when engaged with said power drivers, coupling the firstmember to the drivers for operation by the latter; and means forcontrolling the causing means.

3. In a power operated typewriter, a part to be actuated, a pair ofpower rollers; means connected to said part and mounted between saidpower rollers, including a rockable member and a coupling member carriedthereby adapted to engage and be operated first by one` and then by theother of said 'power rollers, said coupling member when engaged with`one power roller being operated thereby` to rock said rockable membertoactuate saidpart and at the same time carry the coupling member into aposition to engage the second power roller for operation thereby, saidcoupling element, when engaged with the second power roller, rockingsaid rockable member to a position in which the coupling member mayagain belengaged with the first power roller and, simultaneously withsaid second rocking movement, actuating said part; means to cause saidcoupling member to engage said power rollers in the alternate positionsof the rockable member, and a key for controlling the last named means.

4. A power mechanism'for typewriters comprising a. pair of poweroperators, a support member pivoted for rocking movement from each ofsaid operators toward the other, an element carried by said supportmember and adapted to couple said support member to said operators foroperation by one or the other of said operators according to theposition to which the support member is rocked, means for operativelyengaging the coupling element with one of the power operators in eitherof the rocked positions of said support member, and a key forcontrolling the enaging means.

5. In a power operated typewriter, a pair of rotary power operators;means adapte'd to be operated by said operators and mounted for movementbetween alternate positions from one of which positions said means maybe moved by one of said operators to the other alternate position inwhich said means may be operatively coupled with the other operator,said means including a rotary element engageable with the respectiveoperators in said positions to rendor said means operable by therespective power operators, and including means `for rotatably engagingsaid element with said operators; and means for rendering the engagingmeans efl'ective.

6. A power mechanism for typewriting machines comprising a pair of powerrollers, a frame pivoted to swing between said power rollers; asubstantially circular member eccentrically pivoted to said framebetween said rollers and adapted to engage and be actuated by one of sid rollers, according to the position of said frame, when said member isinitially rotated a small amount, said member, when rotated by eitherroller, causing said frame to move to a position to permit similarrotative engagement with the other roller for restoraton of saidrqtation, means in both positions of said frame.

7. A power Operating mechanism for typewriters comprising a pair ofpower rollers, a cam frame mounted to Swing between said power' ing saidcam to prevent said partial rotation in either of the positions of saidframe, and means `for releasing said detent operable in either of thepositions of said irame.

8. In com-bination with a shift mechanism having a part mounted formovement between two case shift positions, a pair of separate poweractual-,ing members: means connected to said part and engageable withboth of said members for operation by one or the other of said membersaccording to the position of said part and y including a couplingelement and means to engage the coupling element'with said members; andmeans for rendering the engaging means effective in either position ofsaid part, including a key movable in one direction to cause thecoupling element to engage one actuating member in one position of thecase shiitable part and movable in another direction to cause thecoupling element to engage the 'other actuating member in the otherposition of the case shiftable part.

9; In a, machine of the class described, a pair of separate poweroperators, a device alternately engageable with one or the other of saidoperators and, when engaged with either operator, being actuated therebyto a position to be ensaid device.

-eective with said device in one position and movable in anotherdirection to renderthe causing means efiective in the alternate positionof RONALD D. DODGE.

REFEEENCES CITED The following references are of record in the file ofthis 'patent:

UNITED STATES PATENTS Number Name Date 1,155,445 Sargent Oct. 5, 19151,688,380 Dorsey Oct. 23, 1928 1,945,097 Thompson et al. Jan. 30, 1934 e2,188,935 Wittenmyer Feb. 6, 1940 2,275,759 Helmond Mar. 10, 19422,331,827 Dennis Oct. 12, 1943

